You should check Rod Harden out. (www.rodharden.com) His stuff covers the spectrum, and he's pretty up front about what to expect. Try the kinky section-- might be close to what you like in a story.
I like *some* bestiality, particularly where it plays with primal human fears. Clever, real, and not yet another situation with a dog (climb, insert, spunk, knot, pool). Parker's recent romp with gorillas, "Keeper", needed plot work by a good editor-- more research on gorilla behavior and how a zoo works-- but it's still extremely well written, and well, it's Parker.
Scatology is just gross, to me. Can't get into it. Haven't read anything that makes it remotely appealing as Dom or Sub.
Sometimes a story doesn't need much of a plot... "JoAnn's Last Anniversary" has one, but it's in the background while cavity searches and bully prison guards are in the foreground. It wasn't gratuitous or the purely "blondes with big tits" sugar candy that is prevalent on the forum. The characters are believable and the heroine is sympathetic.